Damage intestines. The risks of having an umbilical hernia are that intestines can become trapped inside (incarcerated), and their blood supply can then be cut off (strangulation). That could cause necrosis (death) of that part of intestine, which could lead to a hole in the intestine wall. This is very rare but is serious.
Usually untreated hernias just may cause some pain.

The . The biggest question here is what should your husband do. He initially had two differing medical opinions but his condition has worsened significantly since then and the third opinion is he needs surgery. If he doesn't trust that input, he can be evaluated by a general surgeon.
What is a hernia? A hernia is a weak point in the muscle that lets abdominal contents pop through. With an umbilical hernia; you can see bulging at the belly button.
What is the risk of an untreated hernia? If a piece of the bowel pops through the hole in the abdominal wall and it canâ€™t be pushed back in, that part of the bowel may be deprived of oxygen and can die. Yes, that would be very serious.
Currently your husband is making a slow decision over the course of a number of months about whether he wants medical intervention. When will your husbandâ€™s case go from a routine prescheduled surgery to a medical emergency? : if he can not push the contents from his abdomen back into the abdomen with use of gentle pressure. This is even more serious if he can not reduce the hernia and if he develops nausea, vomiting, severe abdominal pain or a fever. The first scenario is usually uncomplicated; the second scenario is now quite complicated and can life threatening depending on how much damage has been done.
Please ask your husband to read this medical response. It is clear that you love him and cared enough to obtain this information. I will not even try to provide non-surgical recommendations at this point; because he has now had two medical opinions that he needs surgical intervention. Your husband is lucky to have a wife who wants him to be healthy.